The investigation on antimicrobial mechanisms is a challenging and crucial issue in the fields of food or clinical microbiology, as it constitutes a prerequisite to the development of new antimicrobial processes or compounds, as well as to anticipate phenomenon of microbial resistance. Nowadays it is accepted that a cells population exposed to a stress can cause the appearance of different cell populations and in particular sub-lethally compromised cells which could be defined as viable but non-culturable (VBNC). Recent advances on flow cytometry (FCM) and especially on multi-parameter flow cytometry (MP-FCM) provide the opportunity to obtain high-speed information at real time on damage at single-cell level. This review gathers MP-FCM methodologies based on individual and simultaneous staining of microbial cells employed to investigate their physiological state following different physical and chemical antimicrobial treatments. Special attention will be paid to recent studies exploiting the possibility to corroborate MP-FCM results with additional techniques (plate counting, microscopy, spectroscopy, molecular biology techniques, membrane modeling) in order to elucidate the antimicrobial mechanism of action of a given antimicrobial treatment or compound. The combination of MP-FCM methodologies with these additional methods is namely a promising and increasingly used approach to give further insight in differences in microbial sub-population evolutions in response to antimicrobial treatments.

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The purpose of this article is to discuss emerging trends in the development and implementation of locally based action directed at crime prevention and community safety in Canada. The discussion centres on the results gleaned from the research and evaluation of specific community-based projects that have been supported under the National Crime Prevention Strategy. Results from some of the projects indicate reductions in offending, improved school attendance and academic achievement, decreased levels of violence and aggression, increased prosocial behaviours, and improved community safety. Despite the considerable progress, many challenges remain in the development of individual and community-based safety initiatives.

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In-vitro reaction mixtures were set up containing bacteria, human serum, human neutrophils and ampicillin or cefotaxime at the MIC, MIC/2 or MIC/4. Serum was untreated, heat-inactivated, absorbed or both. Five indices measuring intra- and extracellular killing were calculated and the effects of heat-labile and absorbable serum factors and of the various concentrations of antibiotics on these indices were calculated. Both heat-labile and absorbable factors enhanced intra- and extracellular killing; antibiotics had a similar effect except that phagocytosis was reduced. Antibiotics at MIC/4 exerted as great an effect as did higher concentrations and this was especially so for cefotaxime. Both heat-labile and absorbable serum factors had a greater effect on all five indices the lower the concentration of antibiotic with advantage for cefotaxime. In the presence of immunological serum factors the overall effect against Salmonella enteritidis is maintained as the concentration of antibiotic falls below the MIC and this is especially seen in the presence of cefotaxime.